In recent years, concern about food safety has been growing. The use of food additives in different countries is limited by specific regulations. Therefore, analytical methods that simultaneously determine artificial sweeteners and preservatives are advantageous. High performance liquid chromatography has been the most popular choice for the determination of food additives. In this study, reversed-phase liquid chromatography was developed for the separation of alpha-aspartame, sodium saccharin, acesulfame-K, vanillin, sorbic acid and benzoic acid. The effects of the proportion of the organic modifier on the chromatographic separation were investigated in order to separate these additives. The results showed that optimum chromatographic separation for these compounds takes place when the acetonitrile content in the mobile phase was 15% containing ammonium acetate buffer (0.005M). It was concluded that the best separation was obtained with YMC-ODS pack column by using this mobile phase at pH 4.0. All additives were separated within 40 min. The RP-HPLC-UV method was validated in terms of LOD/LOQ, linearity, recovery and repeatability. This method was used for the determination of a-aspartame, acesulfame-K and benzoic acid in cola and instant powder drinks.